anyone know if these halogen lamps will work for the projector setup???? how is it compare to metal halide!?? i thought about trying it out, it's inexpensive and it has $0.99 for replacement bulbs.

500W quartz halogen flood lamps - $12.99, info here


$0.99 bulb replacement

bulbs info here

No, not enough color, too hot, not a point source.

I have a few of those in various sizes. I was going to mount two 250 watt bulbs close together inside the 500 watt housing but gave it up as impractical. Even with my method which would use shorter tubes to achieve a smaller arc, the total lumen produced by halogen lights is about 18 - 22 lumen per watt maximum. Remember halogen are just slightly more efficient incandescent lamps. The total lumen per watt produced by metal halide is at minimum 60+ and could peak as high as 100 lumen per watt.
Do the math, in the worst case scenario even if you had all the efficiency out of the halogen you will be lucky to achieve 10000 - 11000 lumen but you use 500 watts of energy to do it but remember you won't get that with the long tubes in a point of light pj design because much of it will not hit the fresnel's sweet spot. A metal halide lamp of 250 watt will produce more total lumen likely around 17000 to 20000. The smaller arc lends itself to the design of most of the pj's here.
On top of that, the reflective housing of those halogen lamps is designed to fan the light out not concentrate it. Then you have the excessive heat issues to deal with, colour rendition etc....

A halogen lamp can work fine and give great color. The main problem is the heat. There is a 360 watt 82V reflector lamp that is almost as bright as our PJ but you will have a lot of fans to cool them.

http://cgi.ebay.com/3-New-Ushio-Halogen-Pr...emZ230109829955

This is a good cheep way to start a PJ. You will need a diode block to make the lamps run on 110V there is one in every OHP.

The OHP lamp have a short life but they are cheep.

Heh... I love the opposite opinions we always get here..!
I should probably throw this out there... I don't know about SuperJETT or gumshoe99; but arizonavideo has almost certainly actually tried at least a few halogen bulbs. I know I haven't, I'm mostly just repeating what I've heard here and elsewhere on the forum...

Maybe I can combine the 3 posts... which are all correct IMO.

Generially it's not a very good light source. If you're looking for a "proof of concept" light, go ahead and try it, but if you're building "for keeps" then you will probably want to use a metal halide.

The advantages you'll get are, better brightness:heat ratio (AKA they're more efficient*), the light will be more "white" so colors will be projected more accurately, and they'll generially be closer to a point light source which is generially accepted to help...

The big down side to MH of course is the cost. Halogen = super cheap to start ($13), super cheap to maintain ($1) while MH bulbs are pretty darn expensive to start ($40+ for a balast and $40+ for the bulb (could end up costin' ya $250 without too much trouble)) and relitively very expensive to maintain ($40+ for the bulbs).

So, if you're trying to get something done without risking too much, go halogen (with more fans). Or if you're going for a first and only (at least for a while) build, go MH.

*More efficient: more light and less heat

I've tested quite a few of these lamps in different styles and sizes, even some shaped like normal household lightbulbs. My initial reactions were probably positive at least in the beginning. I too thought I was on to something. I didn't go back and read exactly what I posted before so I can't really recall what I said a few months ago but I do know the final conclusion.

The small cone shaped halogen lamps are probably the best of the halogen type lamps they are often used in ohp but very expensive to run. Except for the duller colour it would be tempting to use one in cases where you didn't want to use a ballast but you'd have to find a long life one at a good price. My ohp has a similar funnel shaped halogen lamp but it's 410 watts 82 volts. The problem is they only last about 80 hours or so. I do agree that they seem much brighter because of the small lamp and the built-in reflector's shape which maximizes how it hits the fresnel. When I first mounted an lcd on the ohp and shot a picture on the wall I was excited and thought the image was perfect because I had nothing else to compare it to. It is much better than the long tubes in brightness and crispness of the image. I've seen that for myself.

The long tubes you are asking about Solarex are rated at 2000 hours and only cost $1 but in my tests they were not as bright for the high wattage. The 500 watt lamp was so hot that I had to use 2 pieces of tempered glass. The glass on the lamp enclosure plus another piece in the pj and two 120 mm fans and still the lcd darkened very quickly where I had to turn the lamp off for fear of damaging the lcd. My temporary setup box no doubt was to blame also because it didn't have proper airflow so I have to take some of the blame but those things are hot. The reflector design probably contributes something to the heat effect by pushing all the heat forward. A fan mounted on top of the lamp housing and slightly on a backward angle might help draw some of the heat away.

Whatever you do, don't use those lamps unprotected, use them in a worklight housing of the proper rating with the safety glass on. In my tests which I never completed I was going to put the two 250 watt lamps in a 500 watt rated housing. I was just going to drill holes to position the lamp holders.

When I was testing these tube lamps I was satisfied with the image to a degree although there is something missing in the colour and I thought the picture was ok but when I compared to the mh there was really no comparison. There was less light wasted with the shorter 150 watt, 250 watt and 300 watt tubes so I think two of the 250 close together in the same housing would have surpassed a single 500 watt lamp in brightness but the heat issue would have been the same. The total lumen are the same but the shorter arc works better with the rear fresnel.

If that's all I had I would use them, it's not like they won't work. In the long run though you will want something better.

Search the site this topic has come up a few times before.

btw) If you factor in the hydro over the long haul mh wins in cost but as was pointed out it has a higher startup cost.

A halogen lamp has a CRI of 100 none of the MH lamps can do that so all the colors will look with one.

The color temp is too low at 3200K for most lamps the reflector lamps can remove some of the extra red and can have a color temp up to 5500k.

You will need to lower the red driver on the LCD to get chrisp whites. The ebay lamps were three for about $20.00 shipped.

You can get your whole PJ up and runing cheep and after you get tires of changing lamps go to a MH setup.

I have always liked cheep.

Buy a used OHP with a 360 or 410 watt lamp for $20.00 use the triplet and fresnels lamp and buy the 10.6 LCD and controler.

Or a cheep 15"

The luman is around 2500 raw for the ENX lamp and the standard triplet setup. That would give you about 125 lumans with a LCD. Thats the same as many LL projectors.

thanks or the great information guys! these cheap halogen lights seems ok upfront. i was mainly concerning with the color temp, and heat. the plus is it doesn't seem to use/need a ballast to power it. and $0.99 for bulbs is pretty good. maybe there's a color correction filter we can use inline before the lcd panel may make an improvement in the pictures.

for now, i guess I'll use the 400w EYE MH bulb that i bought last year, it's still in a box in a closet next to a stripped Samsung monitor. i detoured a for a while with this project and now i'm picking it up again. Although since then I have looked at several other monitors, one of which is a POLAROID 15" LCD HDTV ready, man too tempting.....

btw, it's funny i join on the same day as arizonavideo and i only have a few posts, what a post whore!!! j/k

post whore

post whore

Yep, post whore

What about using those LARGE 400 Watt MH lamps they sell at home depot? We use them at work for lighting the warehouse and they are so bright you can't stare at it!

No, actually I don't think i've seen them mentioned before. Sounds like a good idea though, give it a try and let us know how it goes

My first projector, I was intending to use one of those lamps. I bought an overhead bay fixture, which had the ballast, lamp and mogul all in one package, then I took that apart.

It would have worked fine, the actual arc chamber in those lamps is similar to the ones in the LL lamps. I sold the lamp, mogul and ballast, however, in favor of one of the Ushio lamps that LL sold at the time, because I wanted the smaller form factor.

The only real downside to those huge lamps is that you will need a large reflector.